Michigan Test for Teacher Certification (MTTC) Secondary Integrated Science Practice test

What defines homogeneous mixtures?

1. Mixtures that can be easily separated by hand

2. Mixtures with a uniform composition throughout

3. Mixtures containing large particles

4. Mixtures that settle over time

The correct answer is: Mixtures with a uniform composition throughout

Homogeneous mixtures are defined by their uniform composition throughout, meaning that the individual components are evenly distributed and not easily distinguishable. This characteristic makes it impossible to identify the different substances within the mixture, as they blend together completely. Common examples of homogeneous mixtures include saltwater, where the salt dissolves evenly in water, and air, which is a mixture of different gases that exist in a consistent ratio. The other options, while descriptive of certain types of mixtures, do not accurately capture the defining feature of homogeneous mixtures. For instance, some mixtures might be easily separable by hand, could contain large particles, or might settle over time, but these traits describe heterogeneous mixtures rather than homogeneous ones. In contrast, a homogeneous mixture maintains a consistent and uniform appearance, regardless of the amount or nature of its components.